River Pebbles (Sandstone and Quartzite)
SiO2 (Quartz) dominated clastic rocks
Category
Browse sedimentary (base), then artificial specimens identified by the Rock Identifier community.
River Pebbles (Sandstone and Quartzite)
SiO2 (Quartz) dominated clastic rocks
Jasper and Basalt (Mixed Breccia or Chert)
Silicon Dioxide (SiO2) with Ferromagnesian silicates
Quartz
Quartz (SiO2 - Silicon Dioxide)
Garnet Schist
Almandine-Garnet Mica Schist
Garnet Schist
Almandine-Muscovite Schist
Banded Gneiss
Gneiss (Metamorphic rock of variable mineralogy, often quartz-feldspar base)
Banded Slate or Siltstone with Quartz/Calcite Veins
Protolith-derived Siltstone or Slate (varies based on degree of metamorphism)
Exposed Aggregate Concrete (Pea Gravel)
Concrete with Siliceous Alluvial Gravels
Quartz Druzy (on Calcedony/Quartz base)
Silicon Dioxide (SiO2)
Muscovite Mica
Muscovite (Potassium Aluminum Silicate Hydroxide Fluoride), KAl2(AlSi3O10)(OH,F)2
Red Jasper
Jasper (Silicon Dioxide based crypto-crystalline Quartz with Iron inclusions)
Opal
Hydrated silica (SiO2·nH2O)
Clear Quartz crystals on a Matrix base (Geode fragment)
Silicon Dioxide (SiO2)
Coquina
Coquina (a type of limestone)
Graphite
Graphite (C)
Painted Pet Rock (Quartzite/Sandstone base)
Silicon Dioxide (SiO2) with anthropomorphic acrylic embellishments
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
Biotite Mica
Biotite, K(Mg,Fe)3AlSi3O10(F,OH)2
Fossilized Shark Tooth (Basal Bone)
Otodus sp. (Mineralized Hydroxyapatite)
Asphalt (Bituminous Concrete)
Bituminous mix containing aggregates and petroleum-based binder (CnH2n+2)
Jasper (Green Jasper / Bloodstone variant base)
Silicon Dioxide (SiO2) with impurities of chlorite and iron oxides
Concrete
Hydrated Portland Cement Aggregate Composite
Red Jasper (Siltstone or Chert-based Jasper)
Silicon dioxide with hematite (SiO2 + Fe2O3)
Muscovite Mica
Muscovite (KAl₂(AlSi₃O₁₀)(F,OH)₂))
Chert (Jasper or Flint variant)
Chert (composed of microcrystalline quartz, SiO2)
Jasper (likely a variety of Yellow or Mustard Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Quartz Druse (on Chalcedony/Agate base)
Silicon Dioxide (SiO2)
Biotite Mica
Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)
Mica (likely Muscovite)
Muscovite / KAl2(AlSi3O10)(OH)2
Clay (as a rock-forming material)
Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)
Quartz Druzy on Agate (River Cobble)
Silicon Dioxide (SiO2)
Sandstone
Sandstone (composed primarily of sand-sized minerals or rock grains)
Conglomerate
Conglomerate
Yellow Jasper
Silicon Dioxide (SiO2) with hydrated iron oxide impurities (Goethite)
Concrete Fragment
Hardened Portland Cement Composite
Aquamarine and clear quartz
Aquamarine (Be3Al2Si6O18), Quartz (SiO2)
Pebble (likely Sandstone or Granitic Pebble)
Clastic Sediment (or specific rock type, e.g., Arenite, Granitoid Pebble)
Chert (often called Flint or Jasper based on color)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (often called Flint or Jasper based on color)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (often called Flint or Jasper based on color)
Microcrystalline Silica (SiO2)
Muscovite Mica
Muscovite (Potassium Mica) KAl2(AlSi3O10)(OH)2
Sandstone
Sandstone (clastic sedimentary rock, composed predominantly of sand-sized minerals or rock fragments)